Annual wintertime water‐level drawdowns are a common management strategy in recreational lakes; however, few studies have estimated their relative impact on lake littoral habitat among a set of typically co‐occurring anthropogenic stressors including lakeshore development and herbicide application. Within 21 Massachusetts, USA lakes that represented a drawdown magnitude gradient (0.07–2.26 m), we assessed depth‐specific littoral habitat (coarse wood, sediment, macrophytes) at two sites adjacent to forested or developed shorelines. Using generalized linear mixed models, we found coarse wood abundance and branching complexity was not correlated with drawdown magnitude but was primarily explained by the presence of lakeshore development. Drawdown magnitude was negatively correlated with silt cover and positively correlated with coarse substrate cover, with effects further varying by depth (0.5 m vs. 1 m). Macrophyte biomass and biovolume were negatively correlated with drawdown magnitude with effects also varying by depth for biomass. Macrophyte taxa with annual longevity strategies (e.g., Najas flexilis) and amphibious growth forms increased in biomass proportions with drawdown magnitude. Distance‐based redundancy analyses suggested macrophyte taxa composition was driven by drawdown magnitude, coarse substrate, alkalinity, water transparency, and herbicide use. These results suggest the importance of water quality and depth on macrophyte assemblage responses to winter drawdowns and the potential to develop drawdown‐tolerant macrophyte assemblages. Altogether, understanding the unique impacts of anthropogenic stressors on littoral zone habitat across heterogeneous environmental lake conditions can help minimize impacts to lake ecological integrity while maintaining recreational value.

中文翻译：

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年度冬季水位下降影响美国马萨诸塞州湖泊的物理生境结构和大型植物

年度冬季水位下降是休闲湖中常见的管理策略。但是，很少有研究估计它们在一系列典型的人为胁迫源（包括湖岸发育和除草剂施用）中对湖滨栖息地的相对影响。在美国马萨诸塞州的21个代表下降幅度梯度（0.07–2.26 m）的湖泊中，我们评估了与森林或发达海岸线相邻的两个地点的特定深度沿岸生境（粗木，沉积物，大型植物）。使用广义线性混合模型，我们发现粗木的丰度和分支的复杂性与水位下降量无关，而主要是由湖岸发育的存在来解释的。沉降量与淤泥覆盖率呈负相关，与粗基质覆盖率呈正相关，效果因深度而进一步变化（0.5 m与1 m）。大型植物的生物量和生物量与下降量呈负相关，生物量的影响也随深度而变化。具有年度寿命策略的大型植物类群（例如，眼镜蛇（Najas flexilis）和两栖生长形式的生物量比例随着下降量的增加而增加。基于距离的冗余分析表明，大型植物类群的组成是由回落量，粗基质，碱度，水透明性和除草剂的使用决定的。这些结果表明，水质和深度对大型植物群落对冬季降水的响应具有重要意义，并具有发展耐耐水生植物群落的潜力。总体而言，了解人为压力源对跨异质环境湖泊条件下沿岸带栖息地的独特影响，可以在保持娱乐价值的同时，将对湖泊生态完整性的影响降至最低。